The Mechanism And Experimental Research On Ultrasonic Vibration Assisted Diamond Wire Sawing Monocrystalline Silicon

With the rapid development of the electronic chip industry,the requirements for sawing monocrystalline silicon wafers is greatly raising.The ultrasonic vibration assisted diamond wire sawing is proved to be the most valid process to obtain the high efficiency and high quality sawing at the same time,witch is very difficult for the current sawing process.Most scholars concentrated on the experimental study of sawing brittle material by using ultrasonic vibration assisted wire saw,rather than the theoretical mechanism of effects on sawing force and forming of workpiece surface caused by ultrasonic vibration.In this paper,the theoretical mechanism of transverse ultrasonic vibration assisted diamond wire saw sawing monocrystalline silicon is studied by theoretically and experimental methods.The main research work includes:The vibration of axial moved diamond wire saw was theoretically researched,the vibration model of wire saw with ultrasonic vibration is established.Then the rationality of the linear vibration hypothesis was proved theoretically.It was also proved that the reciprocating movement of wire saw has no effect on the vibration response of sawing point.The motion path of any single particle on the surface of wire saw driven by ultrasonic excitation was deducedTheoretical modeling and research on sawing force under ultrasonic excitation were carried out.A novel microscopic model of the single particle sawing force with ultrasonic vibration was proposed by combining the vibration impact load model with the single abrasive sawing force model of traditional sawing.The novel single particle sawing force model was verified by finite element method.Then a macroscopic model of the total sawing force of the multi-particle wire saw was established based on the statistical law of macroscopic distribution of particles.The forming mechanism of workpiece surface morphology with ultrasonic excitation was studied.A simulation method of workpiece surface morphology with ultrasonic vibration assisted diamond wire saw was proposed based on dynamic contour sampling method.Firstly,the surface topography model of diamond wire saw was established.Then the path equation of any particle on the surface of wire saw was derived,and an innovative dynamic contour sampling method was introduced.Thedynamic contour sampling method was modified by establishing a simplified material removal model.Finally,the simulation results of workpiece surface topography were obtained.The experiments of ultrasonic vibration assisted wire sawing and traditional wire sawing were conducted respectively in multiple working conditions.The results show that the sawing force of ultrasonic vibration assisted sawing is 25.91%~42.13% lower than that of traditional sawing.The average error of theoretical and experimental values of sawing force is 7.50%.The validity of theoretical model of sawing force is verified.With the assistance of ultrasonic vibration,the surface morphology of workpiece is improved,and the roughness value of workpiece is reduced by 18.89% on average.The measured results of workpiece surface topography were similar to the simulation results,and the average error of the measured and theoretical workpiece surface roughness value is 6.64%.The validity of the theoretical model of workpiece surface topography simulation is verified.